GB1252673A - - Google Patents

Abstract

1,252,673. Clocks and watches. SOC . ANON. DES ETEBS LEON HATOT. Feb.17, 1969 [Feb.19, 1968], No.8467/69. Heading G3T. In a system for synchronizing the mechanical oscillator of a timing device, and including a radio receiver 20 for receiving a periodic radio synchronizing signal, and a winding BS connected to receive the output of the receiver thereby to synchronize the oscillator, a switching device 22 is controlled by the oscillator and electrically connected to prevent energization of the synchronizing winding except when the oscillator is within a predetermined limited range of positions in which the synchronizing signal is effective and which corresponds to a small fraction of the repetition period of the synchronizing signal. The switching device 22 may be in series with the winding BS as illustrated in Fig. 2, or in the power supply circuit or a stage of the receiver 20. One form of switching device 22 comprises a transistor in the emitter-collector circuit of which the coil BS is connected, and in the base-emitter circuit of which is connected a pick-up coil, positioned in relation to a moving magnet system carried by a balance or pendulum so that the transistor is rendered conducting during a desired fraction of the period of oscillation of the balance or pendulum. In other embodiments, Figs.6 and 7 (not shown) a switching transistor is rendered conducting by pulses from a circuit maintaining the oscillations of a balance and comprising a further transistor and drive and pickup coils; whilst in further embodiments, Figs.9 to 11 (not shown) the radio synchronizing signal is applied to one or both of the drive and pick-up coils in the oscillation maintaining circuit, the transistor of which functions as the switching device. The system may also include a filtering circuit Fig. 1 (not shown) for rendering ineffective all parasitic signals received during the intervals between the synchronizing signals.